Of course, you could add Ringo Starr to the list of admirers in the audience, but he covered “Act Naturally,” the Buck Owens hit at the height of the Beatles’ success, so he’s probably a longtime country fan.

With the late Johnny Cash and Waylon Jennings, Nelson and Haggard were members of the Highwaymen, and Nelson began Sunday night’s (Jan. 26) medley with “The Highwayman,” a Jimmy Webb composition about reincarnation that may be the most unlikely country hit ever. Kristofferson then joined in for what turned out to be an appropriately ragged and celebratory performance.

Haggard, of course, is one of Nelson and Kristofferson’s peers, but Shelton seemed in total awe and having the time of his life as he and Haggard swapped verses on “Okie From Muskogee.” By the time Nelson closed the medley with “Mammas Don’t Let Your Babies Grow Up to Be Cowboys,” it appeared as though everyone in the arena was swaying, including Kacey Musgraves, Keith Urban, Taylor Swift and singer-songwriter Ed Sheeran.

It was the end of an eventful few days for Kristofferson, who was presented the Recording Academy’s lifetime achievement award during ceremonies on Saturday. Other lifetime achievement recipients included the Beatles, the Isley Brothers, Kraftwerk and the late zydeco legend Clifton Chenier.